Evidence for nu(mu) -> nu(tau) appearance in the CNGS neutrino beam with the OPERA experiment

Agafonova, N.; Aleksandrov, A.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Asada, T.; Autiero, D.; Dhahbi, A. B.; Badertscher, A.; Bender, D.; Bertolin, A.; Bozza, C.; Brugnera, R.; Brunet, F.; Brunetti, G.; Buonaura, A.; Buontempo, S.; Buettner, B.; Chaussard, L.; Chernyavsky, M.; Chiarella, V.; Chukanov, A.; Consiglio, L.; D'Ambrosio, N.; Lellis, G. D.; Serio, M. D.; Amo, P. D.; Crescenzo, A. D.; Ferdinando, D. D.; Marco, N. D.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Ereditato, A.; Favier, J.; Ferber, T.; Ferone, G.; Fini, R. A.; Fukuda, T.; Galati, G.; Garfagnini, A.; Giacomelli, G.; Goellnitz, C.; Goldberg, J.; Gornushkin, Y.; Grella, G.; Grianti, F.; Guler, M.; Gustavino, C.; Hagner, C.; Hakamata, K.; Hara, T.; Hayakawa, T.; Hierholzer, M.; Hollnagel, A.; Hosseini, B.; Ishida, H.; Ishiguro, K.; Ishikawa, M.; Jakovcic, K.; Jollet, C.; Kamiscioglu, C.; Kamiscioglu, M.; Katsuragawa, T.; Kawada, J.; Kawahara, H.; Kim, J. H.; Kim, S. H.; Kimura, M.; Kitagawa, N.; Klicek, B.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Lauria, A.; Lenkeit, J.; Ljubicic, A.; Longhin, A.; Loverre, P.; Malgin, A.; Mandrioli, G.; Marteau, J.; Matsuo, T.; Matveev, V.; Mauri, Nicoletta; MEDINACELI VILLEGAS, Eduardo; Meregaglia, A.; Migliozzi, P.; Mikado, S.; Miyanishi, M.; Miyashita, E.; Monacelli, P.; Montesi, M. C.; Morishima, K.; Muciaccia, M. T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Nakatsuka, Y.; Niwa, K.; Ogawa, S.; Okateva, N.; Olshevsky, A.; Omura, T.; Ozaki, K.; Paoloni, A.; Park, B. D.; Park, I. G.; Pastore, A.; Patrizii, L.; Pennacchio, E.; Pessard, H.; Pistillo, C.; Podgrudkov, D.; Polukhina, N.; Pozzato, Michele; Pretzl, K.; Pupilli, F.; Rescigno, R.; Roda, M.; Rokujo, H.; Roganova, T.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Ryazhskaya, O.; Sato, O.; Sato, Y.; Schembri, A.; Schmidt Parzefal, W.; Shakiryanova, I.; Shchedrina, T.; Sheshukov, A.; Shibuya, H.; Shiraishi, T.; Shoziyoev, G.; Simone, S.; Sioli, Maximiliano; Sirignano, C.; Sirri, Gabriele; Spinetti, M.; Stanco, L.; Starkov, N.; Stellacci, S. M.; Stipcevic, M.; Strauss, T.; Strolin, P.; Suzuki, K.; Takahashi, S.; Tenti, Matteo; Terranova, F.; Tioukov, V.; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J. L.; Wilquet, G.; Wonsak, B.; Yoon, C. S.; Yoshida, J.; Yoshimoto, M.; Zaitsev, Y.; Zemskova, S.; Zghiche, A.

doi:10.1103/PhysRevD.89.051102

The OPERA experiment is designed to search for nu(mu) -> nu(tau) oscillations in appearance mode, i.e., through the direct observation of the tau lepton in nu(tau)- charged current interactions. The experiment has taken data for five years, since 2008, with the CERN Neutrino to Gran Sasso beam. Previously, two nu(tau) candidates with a t decaying into hadrons were observed in a subsample of data of the 2008-2011 runs. Here we report the observation of a third nu(tau) candidate in the tau(-) -> mu(-) decay channel coming from the analysis of a subsample of the 2012 run. Taking into account the estimated background, the absence of nu(mu) -> nu(tau) oscillations is excluded at the 3.4 sigma level.

N. Agafonova, A. Aleksandrov, A. Anokhina, S. Aoki, A. Ariga, T. Ariga, et al. (2014). Evidence for nu(mu) -> nu(tau) appearance in the CNGS neutrino beam with the OPERA experiment. PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY, 89, 051102-1-051102-6 [10.1103/PhysRevD.89.051102].